hardware architecture vs model-- downloadable distros

suaiteach

Having a bit of trouble understanding the acronyms on the names of the distros available for Debian Linux. Trying to find an older distro for an older system, but can't really tell what the difference is between the links or their available software. Also, a reasonably reliable source is convinced that they refer to processor architecture and not to processor model, or even entire chipsets and motherboards. Could somebody please translate the acronyms into english? What exactly are they? What do they refer to?

Here's the link: http://www.debian.org/CD/http-ftp/#stable

And here are the acronyms:

* amd64

* armel

* kfreebsd-i386

* kfreebsd-amd64

* i386

* ia64

* mips

* mipsel

* powerpc

* sparc

* s390

* source

* multi-arch